The present invention relates to an apparatus for crushing containers, for example beverage or food containers formed from plastics, cardboard or light metal.
A large proportion of household waste is in the form of food and beverage containers. This proportion has increased significantly as a result of the increasing use of liquid containers manufactured from plastics materials, for example polyethylene terephthalate (PET). Such containers although very light in weight occupy a substantial space even when empty. At household waste disposal sites such containers can be compacted along with other waste, and in transit from collection points to the household waste disposal sites waste material can be compacted in waste collection trucks incorporating hydraulic crushing arrangements. Within households however there are no satisfactory means available for efficiently crushing disposable containers.
Metallic containers when crushed generally remain in the configuration into which they have been crushed. Unfortunately, simple crushing of containers fabricated from materials such as PET is ineffective as most such containers, although readily crushed, simply spring back to close to their original shape when the crushing force is removed.
Many proposals have been made for crushing non-metallic containers. Generally these rely upon heating the container to be crushed to a temperature at which its physical characteristics are such that the containers do not spring back to their original shape when the crushing force is released. For example, published international patent application WO 00/21725 describes an apparatus for crushing bottles of thermoplastic material by initially filling the bottles with a small amount of steam and then applying a relatively small force manually. In order to avoid a user contacting a heated bottle, a removable holding pot is provided under the apparatus into which the bottle is pressed. This holding bottle does not however take any part in the crushing process itself but merely retains the crushed bottle in a safe manner.
The above-mentioned published patent application makes specific reference to safety issues which arise in apparatus relying upon heating of the container to be crushed. Additional disadvantages arise however given that using heat to facilitate the crushing process requires significant energy inputs and time delays. As a result devices relying upon the application of heat have not found favour.
DE 241402 describes a method and device for reducing the volume of plastic jars by means of a die and ram. After the compression phase the body is forced through an opening provided in the die.